The general aims are (1) to maintain a group of clinical and laboratory investigators who can interrelate their research, (2) to investigate and resolve problems related to clinical cerebrovascular disease, (3) to study the natural history of stroke of various types by using the resources of the Rochester epidemiological facility and to determine whether various forms of management have altered the natural history, (4) to use in vitro and in vivo models of cerebral ischemia and anoxia to investigate temporal sequence of pathophysiologic changes and sequence of molecular alterations to determine the stage at which reversibility of ischemia is possible and to study what processes or agents may help to produce reversal of the ischmic process, and (5) to provide an environment for training individuals for careers of leadership in research, training, and clinical service in cerebrovascular diseases. Clinical studies will include population studies of incidence and prevalence of stroke, mortality trends over a prolonged number of years, contribution of pre-existing cardiac disease to stroke and T.I.A. evaluation of prevalence and significance of asymptomatic carotid bruit, and evaluation of stroke in relation to mitral valve prolapse. An image analysis program will be used to study cerebral ischemia with computed tomography.